Role of the N-terminal domain of the human DMC1 protein in octamer formation and DNA binding

Takashi Kinebuchi, Wataru Kagawa, Hitoshi Kurumizaka, Shigeyuki Yokoyama

    Research output: Contribution to journalArticle

    21 Citations (Scopus)

    Abstract

    The DMC1 protein, a eukaryotic homologue of RecA that shares significant amino acid identity with RAD51, exhibits two oligomeric DNA binding forms, an octameric ring and a helical filament. In the crystal structure of the octameric ring form, the DMC1 N-terminal domain (1-81 amino acid residues) was highly flexible, with multiple conformations. On the other hand, the N-terminal domain of Rad51 makes specific interactions with the neighboring ATPase domain in the helical filament structure. To gain insights into the functional role of the N-terminal domain of DMC1, we prepared a deletion mutant, DMC1-(82-340), that lacks the N-terminal 81 amino acid residues from the human DMC1 protein. Analytical ultracentrifugation experiments revealed that, whereas full-length DMC1 forms a octamer, DMC1-(82-340) is a heptamer. Furthermore, DNA binding experiments showed that DMC1-(82-340) was completely defective in both single-stranded and double-stranded DNA binding activities. Therefore, the N-terminal domain of DMC1 is required for the formation of the octamer, which may support the proper DNA binding activity of the DMC1 protein.

    Original languageEnglish
    Pages (from-to)28382-28387
    Number of pages6
    JournalJournal of Biological Chemistry
    Volume280
    Issue number31
    DOIs
    Publication statusPublished - 2005 Aug 5

    ASJC Scopus subject areas

    • Biochemistry

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